β-Aminobutyric Acid-induced Resistance in Plants

Thehe broad sprectrum protective effect of the non-protein amino acid β-aminobutyric acid (BABA) against numerous plant diseases has been well-documented in the literature. Here, we present an overview of BABA-induced protection in various pathosystems. Contriidictory reports concerning the mechanism of action underlying this type of protection incited us to take advantage of Arabidopsis/pathogen interactions as model systems to investigate the action of BABA at the genetic and molecular level. We present evidence that the protective effect of BABA is due to a potentiation of natural defense mechanisms against biotic and abiotic stresses. In order to dissect the pathways involved in potentiation by BABA describe the use of a mutational approach based on BABA-induced female sterility in Arabidopsi

Fungal model systems and the elucidation of pathogenicity determinants

This is the final version of the article. Available from Elsevier via the DOI in this record.Fungi have the capacity to cause devastating diseases of both plants and animals, causing significant harvest losses that threaten food security and human mycoses with high mortality rates. As a consequence, there is a critical need to promote development of new antifungal drugs, which requires a comprehensive molecular knowledge of fungal pathogenesis. In this review, we critically evaluate current knowledge of seven fungal organisms used as major research models for fungal pathogenesis. These include pathogens of both animals and plants; Ashbya gossypii, Aspergillus fumigatus, Candida albicans, Fusarium oxysporum, Magnaporthe oryzae, Ustilago maydis and Zymoseptoria tritici. We present key insights into the virulence mechanisms deployed by each species and a comparative overview of key insights obtained from genomic analysis. We then consider current trends and future challenges associated with the study of fungal pathogenicity.This review was carried out by members of the EU-Initial Training Network Ariadne (PITN-GA-2009-237936), which provided financial support for C.B., S.D., M.E.G., E.G., E.M., P.V.M., M.M., V.N., M.F.A.N., T.O., M.O.R., K.S. and L.W

Strongly Coupled Magnetic and Electronic Transitions in Multivalent Strontium Cobaltites

The topotactic phase transition in SrCoOx (x = 2.5-3.0) makes it possible to reversibly transit between the two distinct phases, i.e. the brownmillerite SrCoO2.5 that is a room-temperature antiferromagnetic insulator (AFM-I) and the perovskite SrCoO3 that is a ferromagnetic metal (FM-M), owing to their multiple valence states. For the intermediate x values, the two distinct phases are expected to strongly compete with each other. With oxidation of SrCoO2.5, however, it has been conjectured that the magnetic transition is decoupled to the electronic phase transition, i.e., the AFM-to-FM transition occurs before the insulator-to-metal transition (IMT), which is still controversial. Here, we bridge the gap between the two-phase transitions by density-functional theory calculations combined with optical spectroscopy. We confirm that the IMT actually occurs concomitantly with the FM transition near the oxygen content x = 2.75. Strong charge-spin coupling drives the concurrent IMT and AFM-to-FM transition, which fosters the near room-T magnetic transition characteristic. Ultimately, our study demonstrates that SrCoOx is an intriguingly rare candidate for inducing coupled magnetic and electronic transition via fast and reversible redox reactions

La Passagère, un opéra

Opéra sorti du purgatoire. Dans le précédent numéro de Témoigner, nous avons consacré notre rubrique à L’Empereur de l’Atlantis de Viktor Ullmann, cette fois, nous voudrions revenir sur un autre opéra, peu connu également : La Passagère de Mieczyslaw Weinberg. Sa dernière représentation, à Londres, a suscité quelques débats.Opera from out of Purgatory. In the previous edition of Testimony, we devoted our chronicle to The Emperor of Atlantis by Viktor Ullmann. This time, we would like to look at another opera, again one that is not very well-known: The Passenger by Mieczyslaw Weinberg. Its last performance, in London, aroused a few debates.Opera vanuit het vagevuur. In het vorige nummer van Getuigen besteedden we aandacht aan Der Kaiser von Atlantis van Viktor Ullmann. Dit keer hebben we het over een andere opera, die eveneens minder bekend is: The Passenger van Mieczyslaw Weinberg. De laatste voorstelling, in Londen, zorgde voor wat polemiek

The Passenger, an Opera

Opera from out of Purgatory. In the previous edition of Testimony, we devoted our chronicle to The Emperor of Atlantis by Viktor Ullmann. This time, we would like to look at another opera, again one that is not very well-known: The Passenger by Mieczyslaw Weinberg. Its last performance, in London, aroused a few debates.Opéra sorti du purgatoire. Dans le précédent numéro de Témoigner, nous avons consacré notre rubrique à L’Empereur de l’Atlantis de Viktor Ullmann, cette fois, nous voudrions revenir sur un autre opéra, peu connu également : La Passagère de Mieczyslaw Weinberg. Sa dernière représentation, à Londres, a suscité quelques débats.Opera vanuit het vagevuur. In het vorige nummer van Getuigen besteedden we aandacht aan Der Kaiser von Atlantis van Viktor Ullmann. Dit keer hebben we het over een andere opera, die eveneens minder bekend is: The Passenger van Mieczyslaw Weinberg. De laatste voorstelling, in Londen, zorgde voor wat polemiek

New Biocide Foam Containing Hydrogen Peroxide for the Decontamination of Vertical Surface Contaminated With Bacillus thuringiensis Spores

Despite scientific advances, bacterial spores remain a major preoccupation in many different fields, such as the hospital, food, and CBRN-E Defense sector. Although many disinfectant technologies exist, there is a lack for the decontamination of difficult to access areas, outdoor sites, or large interior volumes. This study evaluates the decontamination efficiency of an aqueous foam containing hydrogen peroxide, with the efficiency of disinfectant in the liquid form on vertical surfaces contaminated by Bacillus thurengiensis spores. The decontamination efficiency impact of the surfactant and stabilizer agents in the foam and liquid forms was evaluated. No interferences were observed with these two chemical additives. Our results indicate that the decontamination kinetics of both foam and liquid forms are similar. In addition, while the foam form was as efficient as the liquid solution at 4°C, it was even more so at 30°C. The foam decontamination reaction follows the Arrhenius law, which enables the decontamination kinetic to be predicted with the temperature. Moreover, the foam process used via spraying or filling is more attractive due to the generation of lower quantity of liquid effluents. Our findings highlight the greater suitability of foam to decontaminate difficult to access and high volume facilities compared to liquid solutions

Experimental measurements of propagation characteristics for maritime radio links

International audienceThis paper presents studies, carried out by Télécom Bretagne, concerning new radio technologies (mainly WiMAX, 802.16e) in the maritime environment. The aim of these studies is to reinforce the quality and the robustness of such transmissions. Several measurements were set up to characterize the propagation channel in maritime environment in order to study the communication performances of WiMAX. This characterization was obtained by specific experimental devices, developed and implemented by Télécom Bretagne. The experimentations were carried out at frequencies of 3.5 GHz (Licensed WiMAX Band in France) and 5.8 GHz (Free Band in France). Similar studies [1] and [2] were already carried out, but they did not take into account all the environment characteristics, namely tides and coast relief masking. Our study looks at these parameters for a better understanding of the propagation in operational transmission environments. In this paper, measurements were carried out by measuring the mean received power both for several distances over the sea and for a coastal point-to-point link during long periods. Part of the work presented in this paper has been obtained during the Ex’treme projec

Morphologie, croissance individuelle et dynamique des populations de la tortue verte (Chelonia mydas L.) au banc d'arguin (République islamique de Mauritanie)

The carapace morphology and growth of the Green turtle (Chelonia mydas L.) has been studied in a large (n = 177) sample of animals collected by the Imragen fishermen on the Banc d'Arguin (lslamic Republic of Mauretania). The frequency of anomalies of the scales decreases with age in this species, possibly due to a differentiai mortality between normal and abnormal individuals. The mathematical relation between length and width of the carapace is discussed and the Mauretanian data are compared with those of other areas. There are obvious differences in the shape of the carapace between different breeding populations of green turtles, which quite likely correspond to genetic differences between various breeding populations. The Mauretanian green turtles are quite similar to those breeding on the eastern coast of South-America. Seven age classes can be recognized on the basis of the carapace length. A growth curve of the Mauretanian population of Chelonia mydas L., based upon von Bertalanffy equation, is proposed. The rate of growth decreases sharply after the first breeding season. Sexual maturity takes place at 5.5 years of age, but age at first reproduction apparently varies from one population to the other, probably depending upon fishing pressure. The number of "bachelors" (mature individuals not taking part in reproduction) is apparently greater in areas with the smallest fishing pressur

Mechanical stresses govern myoblast fusion and myotube growth

Myoblast fusion into myotubes is critical for muscle formation, growth and repair. While the cellular and molecular mechanisms regulating myoblast fusion are increasingly understood, the role of biomechanics in this process remains largely unexplored. Here, we reveal that a dynamic feedback loop between evolving cell mechanics and cell-generated stresses shape the fusion of primary myoblasts in vitro. Applying principles from active nematics, we show that myoblast and myotube patterning follows physical rules similar to liquid crystal organization. Remarkably, fusion predominantly occurs at comet-shaped topological defects in cellular alignment, which we identified as regions of high compressive stress. We further find that this stress-driven organization depends on extracellular matrix (ECM) deposition, which mirrors the nematic order of the cell population. Our integrated data, supported by active nematics-based mathematical modeling, accurately predict self-organization patterns and mechanical stresses that regulate myoblast fusion. By revealing the essential role of biomechanics and ECM interplay in myogenesis, this work establishes a foundational framework for understanding biomechanical principles in morphogenesis